[BUG] Old query for Splunk rules migration in the flyout

**Description**
The Splunk migration query is not updated as per the latest UI changes, so it should be reflected in the docs

**Documentation links**
https://www.elastic.co/docs/solutions/security/get-started/automatic-migration#get-started-with-automatic-migration

**Release version**
9.3.0

**Actual result**

**Expected Result**